Tissue distribution study of strychnine, brucine and their metabolites in rat tissue by LC-MS/MS / 中国药理学通报

Aim: To establish an LC-MS/MS method to simultaneously determinate strychnine (STR), brucine (BRU), strychnine N-oxide(SNO) and brucine N-oxide(BNO) in rat tissue, and study their tissue distributions following single intragastric administration of total alkaloids from Semen Strychni at normal and high toxic dose. Methods: Ephedrine hydrochloride was used as the internal standard (IS). Analytes were extracted from tissue samples using liquid-liquid extraction with chloroform. Chromatographic separations were performed on a ZORBAX E-clipse XDB-C18 column(2.1 x 150 mm, 3. 5 μm) with the mobile phase of phase A(water, 10 mM ammonium acetate, adjusted to pH 4. 0 with formic acid) and B(methanol) at a flow rate of 0. 2 mL · min-1. The column temperature was maintained at 30 °C. Mass spectrometric detection was performed on an API4000+ triple quadrupole mass spectrometer equipped with an electrospray ionization (ESI) interface in the positive ion multiple reaction monitoring(MRM) mode. Results: Excellent linearity was observed in all analytes within their linear ranges. In-tra-and inter-day relative standard deviations (RSDs) were less than 14.90%, and accuracies were (85.94 ±1.43)% -(113. 77 ±5.19)%. STR, BRU and SNO distributed in all the tissues in different degree, among which content in kidney and liver was the richest. STR and BRU distributions were low in brain. Conclusions: The developed method is simple, sensitive, specific and reliable, which is suitable for simultaneous determination of STR, BRU, SNO and BNO in rat tissues.

Three new 3,4-seco-cycloartane triterpenes from Gardenia sootepensis.

The plants in the genus Gardenia (Rubiaceae) have long been used as traditional medicines in China. In this study, two new 3,4-seco-cycloartane triterpenes, sootepin J (1) and sootepin K (2), and a novel nor-3,4-seco-cycloartane triterpenes, sootepin L (3), together with two known compounds (4-5), were isolated from the methanolic extract of the leaves and twigs of Gardenia sootepensis. The structures of the new compounds were elucidated by combinations of 1D, 2D NMR experiments and HR-MS data, while the known compounds were identified by comparison of the NMR data with previously published data.

Enzymatic synthesis and characterization of novel biodegradable copolymers of 5-benzyloxy-trimethylene carbonate with 1,4-dioxan-2-one.

Enzymatic ring-opening copolymerization of 5-benzyloxy-trimethylene carbonate (BTMC) and 1,4-dioxan-2-one (DON) was investigated for the first time. Immobilized porcine pancreas lipase (IPPL) on silica particles was selected to perform the copolymerization. A series of novel biodegradable copolymers with different compositions were characterized by (1)H NMR, (13)C NMR, and GPC. The influences of reaction conditions such as polymerization time and catalyst concentration on the yield and molecular weight of the copolymers were also studied. The copolymerizations of different monomer feed ratios were carried out in bulk at 150 degrees C with 4.5 wt per thousand IPPL as a catalyst for 24 h. With the increase of the BTMC molar feed ratio from 20% to 79%, the M(n) of the resulting copolymers increased from 5600 to 63400. Water uptake and static contact angle experiments showed that the hydrophilicity of copolymers could be improved with increasing DON content in the copolymers. Moreover, the in vitro drug release rate (ibuprofen as the model drug) of the resulting copolymers also increased along with the DON content in the copolymers.